JP4695679B2 - Template cleaning method and pattern forming method - Google Patents

Description

  The present invention relates to a method for cleaning a template which is a master disk used in an imprint lithography method used in a semiconductor device manufacturing process, a hard disk manufacturing process, a photoarray manufacturing process, and the like, and a pattern using the template cleaned by this cleaning method. The present invention relates to a forming method.

  In recent years, the nanoimprint method has attracted attention as a technique for forming a fine pattern. In the nanoimprint method, an imprint template having a concavo-convex pattern is brought into contact with a resist applied on a substrate to be processed, the resist is cured, and then the template is released from the resist to form a resist pattern.

When the template is released, the resist may remain on the pattern surface of the template due to a part of the resist pattern being cut. For this reason, in pattern formation by the imprint technique, it is necessary to remove the resist remaining on the template as appropriate.

A technique for removing the resist remaining on the template is described in Patent Document 1. In Patent Document 1, a photocatalyst such as titanium oxide is formed in advance on the pattern surface of a template, and when a resist residue is generated, ultraviolet light is irradiated from the pattern surface as shown in FIG. A method for removing a resist residue by oxidative decomposition using the photocatalytic action of titanium oxide is disclosed. However, when titanium oxide is formed on the template, it is generally necessary to calcinate at 500 ° C. or higher, which causes a problem that the template pattern is distorted, which is difficult in practical use.

Patent Document 2 discloses a method using OH radicals for the purpose of hydrophilizing the resist surface. In Patent Documents 3 and 4, a resist pattern on a substrate to be processed is irradiated with ultraviolet light from the pattern surface side in an atmosphere containing water or oxygen to generate OH radicals or oxygen radicals. A method of thinning a resist pattern by removing a part of the pattern is disclosed.
JP 2005-327788 A JP 2006-186111 A JP 2006-32992 A JP 2004-363444 A

  An object of the present invention is to provide a pattern forming template cleaning method capable of effectively removing foreign matters remaining on a template used in an imprint method, and a pattern forming method using a template cleaned by this cleaning method. To do.

The first invention of the present application includes a step of holding a template having a pattern surface having irregularities, a cleaning agent supplying step of supplying a cleaning agent to a region containing foreign matter attached to the pattern surface of the template, Irradiating radiant light from the surface opposite to the pattern surface, and a cleaning agent excitation step of generating a radical by photoexciting the cleaning agent with the radiant light, and reacting the foreign matter and the radical to react at least the foreign matter It comprises a foreign substance hydrophilizing process for partially hydrophilizing and a foreign substance removing process for removing the foreign substance from the template after the hydrophilizing process.

ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning method of the template which can remove effectively the foreign material which remains on the template used for the imprint method, and the pattern formation method using the template wash | cleaned by this washing | cleaning method can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
An optical nanoimprint apparatus according to the first embodiment of the present invention and a pattern formation method using an optical nanoimprint method using the apparatus will be described with reference to FIGS. 1 and 2, respectively.

FIG. 1 is a schematic diagram illustrating an example of a nanoimprint apparatus 100 used in an imprint method using photocuring. The nanoimprint apparatus 100 selectively includes a substrate to be processed chuck 102 for fixing a substrate to be processed (wafer) 110, a stage 101 for a substrate to be mounted and moved two-dimensionally on the substrate to be processed. An imprint resist applying means 103 for supplying a resist material to the substrate, a template holding mechanism 104 for holding the nanoimprint template 120, and a UV lamp 105 for performing UV irradiation for curing the resist material via the template. . The template 120 for nanoimprint is formed, for example, by forming an uneven pattern by plasma etching on a fully transparent quartz substrate used for a general photomask.

An example of the pattern formation process by the general nanoimprint method using this apparatus 100 is shown in FIG. FIG. 2 is a process cross-sectional view showing a pattern forming method by a general nanoimprint method.

First, as shown in FIG. 2A, after the target substrate 110 is held by the target substrate chuck, the target substrate 110 is relatively moved directly below the imprint resist coating means 103, so that the target substrate 110 is covered. An imprint resist 112 having fluidity was selectively formed in the imprint region 111. The application of the resist 112 was performed by operating the imprint resist application means 103.

Next, as shown in FIG. 2B, the target substrate stage was driven to move the target substrate 110 directly below the template 120 held by the template holding mechanism.

Subsequently, as shown in FIG. 2C, the concave / convex pattern surface of the template 120 is brought close to the main surface of the substrate 110 to be processed so as to sandwich the resist 112 and is brought into contact with the resist 112. At this time, the resist 112 having fluidity is filled in the concave region of the template by capillary action.

After filling, as shown in FIG. 2 (d), after aligning the main surface of the substrate to be processed 110 and the pattern formed on the template 120, the side opposite to the pattern forming surface (uneven surface) of the template 120. From this surface, light irradiation 105 for curing the resist is performed.

Further, after the resist 112 is cured, as shown in FIG. 2E, the template 120 is released to form a resist pattern 113 on the substrate 110 to be processed.

However, as shown in FIG. 3, the resist pattern 113 may be broken when the template 120 is released, and a residual resist 124 may be generated in the concave pattern of the template 120. If the template is continuously used in this state, a common defect occurs in the resist pattern. Therefore, it is necessary to perform a cleaning process for removing the resist 124 remaining in the recesses on the template. With reference to FIG. 4, an example of a cleaning apparatus used for cleaning the template according to the present embodiment will be described. FIG. 4 is a schematic view showing a cleaning apparatus used for cleaning the template according to the present embodiment.

As shown in FIG. 4, the cleaning apparatus 400 according to this embodiment includes a template holding mechanism 401 that holds a template 120 to be cleaned, and a cleaning agent supply mechanism 403 that supplies a cleaning agent 402 to the pattern forming surface of the template 120. And a light irradiation mechanism 404 for irradiating and activating the cleaning agent 402 with light.

As the cleaning agent supply mechanism 403, a cleaning tank for immersing the pattern surface of the template 120 was used. A cleaning agent is supplied to the cleaning tank through a pipe (not shown). The cleaning agent supply mechanism 403 is not limited to the above-described cleaning tank, and any cleaning agent may be used as long as it can supply the cleaning agent to the pattern surface of the template 120. Other examples of the cleaning agent supply mechanism will be described later.

Oxygen water was used for the cleaning agent 402. Oxygen water is obtained by dissolving oxygen gas in deaerated pure water. The cleaning agent 402 is not limited to this oxygen water, and any cleaning agent 402 may be used as long as it generates at least OH radicals when irradiated with light. For example, water or an aqueous solution containing water as a solvent, an aqueous solution containing hydrogen peroxide as a solute, an organic substance, or an alcohol can be used.

The template holding mechanism 401 holds the pattern surface of the template 120 in the direction in which the cleaning agent 402 is supplied. The template holding mechanism 401 can drive and tilt the template 120 to be held in the plane direction and the vertical direction, and drives the pattern surface of the template 120 toward the cleaning agent 402 stored in the cleaning tank. The cleaning agent 402 can be supplied in contact with the pattern surface.

The light irradiation mechanism 404 includes a Xe excimer lamp as a light source. From the Xe excimer lamp, the template 120 is irradiated with light having a wavelength of 172 nm. The light irradiation mechanism 404 according to the present embodiment is provided at a position closer to the surface opposite to the pattern surface than the pattern surface so that light is irradiated from the surface opposite to the pattern surface of the template 120. In addition, the light irradiation mechanism 404 is provided so as to be driven in a planar direction and a vertical direction, and can irradiate light in the vicinity of or in contact with the surface opposite to the pattern surface of the template 120. Furthermore, the light irradiation mechanism 404 is configured to be able to adjust the light irradiation angle with respect to the template 120. Conversely, the template holding mechanism 401 may include a mechanism for adjusting the inclination of the template 120 with respect to the irradiation light.

The cleaning apparatus 400 according to the present embodiment or a part of the mechanism thereof may be provided in the imprint apparatus 100 used for pattern formation shown in FIG. In this case, the template holding mechanism 104 of the imprint apparatus 100 can also function as the template holding mechanism 401 of the cleaning apparatus 400.

Next, a template cleaning method according to this embodiment using the above-described apparatus will be described with reference to FIG. FIG. 5 is a process cross-sectional view illustrating the template cleaning method according to the present embodiment.

First, as shown in the right figure of FIG. 5A, the template holding mechanism 401 further performs cleaning in which the cleaning agent 402 is further accumulated so that the concavo-convex pattern surface (cleaning surface) faces the side opposite to the light irradiation mechanism 404. It is held so as to be directed to the agent supply mechanism 403. The left figure of Fig.5 (a) is an enlarged view of the dotted-line part of the right figure of Fig.5 (a). As shown in the left diagram of FIG. 5A, a resist residual is attached to the pattern surface of the template 120. In the following description using FIG. 5, only the enlarged view of the portion shown in the left diagram of FIG.

Next, as shown in FIG. 5B, the template holding mechanism is driven, the pattern surface including the resist residue 124 of the template 120 is brought into contact with the cleaning agent (oxygen water) 402 in the cleaning tank, and the pattern surface is cleaned. Agent 402 was supplied. At this time, it is desirable that the cleaning agent 402 is immersed in the cleaning agent 402 to such an extent that the cleaning agent 402 does not cover the surface opposite to the pattern surface of the template 120. When the process proceeds to the light irradiation step described later with the cleaning agent 402 supplied to the surface opposite to the pattern surface, the light irradiated from the surface opposite to the pattern surface covers the surface opposite to the pattern surface. This is because the light does not reach the pattern surface side due to being absorbed by 402 or the light reaching the pattern surface is weak, and cleaning may not be performed sufficiently.

Next, as shown in FIG. 5C, with the light-irradiation mechanism in a state where the uneven pattern surface of the template 120 is submerged, the surface opposite to the uneven pattern surface of the template 120 is applied to the pattern surface of the template 120. Then, light with a wavelength of 172 nm (excitation light 105) was irradiated. Although light having a wavelength of 172 nm is slightly absorbed by the template base material quartz, the resist residue 124 and the cleaning agent 402 around it are irradiated. In water excited by light having a wavelength of 172 nm, OH radicals are generated, and the OH radicals start to react with the resist residue. In the case where water or an aqueous solution using water as a solvent is used as the cleaning agent 402, not only light having a wavelength of 172 nm but also light having a wavelength of 200 nm or less is irradiated to the cleaning agent to excite water in the cleaning liquid to generate OH. It is possible to generate radicals. In the present embodiment, after the pattern surface of the template 120 is immersed in the cleaning agent 402, the light irradiation mechanism is driven to contact the surface opposite to the pattern surface of the template 120 by driving the light irradiation mechanism. Light was irradiated in the contact state. When the irradiation light 105 passes through a medium (such as air or water vapor) between the light irradiation mechanism and the template, the light may be absorbed by the medium and the light may not reach the pattern surface sufficiently. However, as described above, the light irradiation mechanism can be prevented from absorbing light in the medium between the light irradiation mechanism and the template by bringing the light irradiation mechanism into contact with the surface opposite to the pattern surface of the template and performing the light irradiation.

However, when the effect of absorption of irradiation light in the medium between the light irradiation mechanism and the template is not so great and a desired amount of light reaches the pattern surface, absorption of light having a wavelength of 172 nm is reduced by purging with nitrogen, for example. Alternatively, when processing such as making the space between the template and the light irradiation mechanism close to a vacuum is performed, the light irradiation mechanism does not necessarily have to contact the surface opposite to the pattern surface of the template. The mechanism may be close to the template.

In addition, in order to suppress the absorption of the irradiation light in the medium between the light irradiation mechanism and the template, the medium between the light irradiation mechanism and the template should not be included in the medium between the light irradiation mechanism and the template so Dry air may be introduced into the space.

Further, in FIG. 5C, light is incident on the template surface perpendicularly, but it is not always necessary to be incident perpendicularly. Depending on the position of the resist residual in the pattern recess, it can also be incident from an oblique direction.

As shown in FIG. 5D, the surface of the resist residue 124 (the contact surface with the cleaning agent 402) gradually becomes hydrophilic due to the OH radical reaction, so the interface between the resist residue 124 and the template 120 (the side surface of the recess pattern). Part). Further, the soaked cleaning agent is excited by light having a wavelength of 172 nm, and the hydrophilic region of the resist residue 124 is expanded. Accordingly, the cleaning agent 402 penetrates into the interface, and the resist residue 124 is peeled off from the template interface. As the reaction proceeds, part of the resist residue 124 becomes water-soluble and may be dissolved.

In addition, oxygen in the cleaning agent 402 is also excited by light having a wavelength of 172 nm to generate oxygen radicals. Since this oxygen radical also has an action of decomposing the resist residue, the OH radical reaction proceeds with respect to the resist residue 124 and becomes soluble, while the oxidative decomposition reaction by the oxygen radical reaction proceeds.

As shown in FIG. 5E, while the resist residue 124 peeled off from the template 120 is irradiated with the light 105 having a wavelength of 172 nm, the action of OH radicals generated from water and oxygen radicals generated from oxygen is further reduced. In response, dissolution and oxidative degradation proceed.

Finally, as shown in FIG. 5 (f), the uneven pattern surface of the template 120 is washed with water to remove the suspended matter remaining in the cleaning agent 402, further replaced with isopropanol, and dried to be processed. Ended. By the cleaning method according to the present embodiment, the resist residue generated on the uneven pattern surface of the template could be completely removed.

In this embodiment, oxygen water is used as the cleaning agent. However, water that generates OH radicals by light irradiation or a solvent containing OH such as alcohol can contain oxygen or ozone. Even in pure water brought into contact with the atmosphere, oxygen is dissolved in the order of several tens of ppm. Even when such (pure) water was used, the effect could be confirmed. Although ozone water alone has an oxidizing action, the resist residue could be removed more effectively by irradiating light with a wavelength of 172 nm from the template side as in this embodiment.

However, when ozone water was supplied to the concavo-convex pattern surface of the template and the light having a wavelength of 172 nm was irradiated from the pattern surface side of the template, the resist residue could hardly be removed. This is because ozone water strongly absorbs light having a wavelength of 172 nm, and OH radicals are generated on the surface of the ozone water irradiated with light, but light does not reach the vicinity of the resist residue, so that excitation can be performed around the resist residue. This is because a radical reaction on the resist residue surface could not occur.

In this embodiment, the cleaning agent is statically supplied. However, the template and the resist may be flown because the irradiation of light that excites the cleaning agent from the template side may be performed, regardless of whether the cleaning agent is stationary or flowing. It is characterized by causing a radical reaction to the resist residue at the residue interface, and when flowing (running water), it is higher because it can be effectively removed from the uneven pattern surface of the template by peeling and decomposing the residue. A cleaning effect can be obtained.

In general, by irradiating an organic material such as resist in the atmosphere with an excimer lamp, it directly acts on oxygen to generate excited oxygen atoms, which can be decomposed into carbon dioxide and water for removal. It is known that there is. However, when the excimer lamp was irradiated in the atmosphere from the pattern surface side of the template, it was confirmed that the residue surface was decomposed because sufficient ozone was supplied. In the initial stage of irradiation, only the cross-linking reaction by short-wavelength irradiation proceeds, so it remained as a strong residue.

(Second embodiment)
The template cleaning method according to the present embodiment is an aqueous solution containing hydrogen peroxide containing ozone and carbon dioxide as a solute instead of oxygen water which is a cleaning agent used in the cleaning method according to the first embodiment. This is a method for cleaning a template using an organic substance. Since other parts are almost the same, detailed description of some processes is omitted.

When an aqueous solution or organic substance having hydrogen peroxide as a solute is used for the cleaning agent, if the light having a wavelength of 172 nm used in the first embodiment is used as excitation light for the cleaning agent, Attenuation will increase. For this reason, a KrCl excimer lamp was adopted as a light irradiation mechanism from an absorption band having a wavelength of 250 nm or less, and the cleaning agent was irradiated with light having a wavelength of 222 nm (excitation light).

Using the same method as in the first embodiment, the excitation light was irradiated through the surface opposite to the concave / convex pattern surface of the template. Hydrogen peroxide generates two OH radicals when irradiated with light having a wavelength of not more than 250 nm and having a wavelength of 222 nm. For this reason, OH radical reaction can be effectively carried out on the resist residue surface, and in the cleaning method according to the present embodiment, the resist residue is removed in about half the processing time as compared with the cleaning method according to the first embodiment. It was able to peel from the template.

The trace amount of carbon dioxide contained in the hydrogen peroxide solution has a role of controlling the potential so that the resist residue peeled from the template and its oxidative decomposition product do not reattach to the template. For this reason, the resist residue peeled off by the excitation effect of light having a wavelength of ozone of 222 nm contained in a trace amount in hydrogen peroxide could be efficiently decomposed into water, carbon dioxide, sulfur dioxide and the like. The resist residue which was peeled from the template by OH radical and ozone oxidation and decomposed was removed with pure water, and the resist surface removal process was completed by drying the template surface.

(Third embodiment)
The template cleaning method according to the present embodiment is a cleaning method using isopropyl alcohol in which carbon dioxide is dissolved as a cleaning agent in place of the oxygen water that is the cleaning agent used in the cleaning method according to the first embodiment. It is. Since the others are almost the same, detailed description is omitted.

In the template cleaning method according to the present embodiment, similarly to the cleaning method according to the first embodiment, a wavelength of 172 nm is passed through the surface opposite to the concavo-convex pattern surface of the template using a Xe excimer lamp (light irradiation mechanism). Irradiated with light. Isopropyl alcohol in the cleaning agent can efficiently absorb light having a wavelength of 172 nm.

Isopropyl alcohol in the vicinity of the interface with the template generated OH radicals by an excitation reaction caused by irradiation with light having a wavelength of 172 nm, and the OH radicals reacted with the resist residue to separate the resist residue from the template. A part of the resist residue that became water-soluble by reaction with OH radicals was dissolved in isopropyl alcohol as a cleaning agent. The peeled and dissolved resist residue was washed away from the concavo-convex pattern surface of the template with isopropyl alcohol. At this time, similar to the cleaning method according to the second embodiment, the carbon dioxide contained in isopropyl alcohol was able to suppress the reattachment of the resist residue exfoliation and dissolution products to the template. After rinsing with isopropyl alcohol as described above, the template was dried to finish the cleaning process.

In this embodiment, isopropyl alcohol is used as the cleaning agent, but the present invention is not limited to this. The same effect was obtained even when a low-molecular-weight alcohol having 4 or less carbon atoms such as methanol, ethanol, propanol or butanol was used.

Further, by using a cleaning agent in which hydrogen peroxide is dissolved in these alcohols, an OH radical reaction can be further effectively generated.

In addition, when a cleaning agent in which oxygen or ozone was further dissolved was used for the cleaning agent, the resist residue and the dissolved matter that were peeled off could be further oxidized and decomposed, and a greater cleaning effect was obtained.

In the present embodiment, light having a wavelength of 172 nm is used, but the present invention is not limited to this. Light having any wavelength may be used as long as it is a light absorption band of the cleaning liquid and has a wavelength that generates OH radicals and transmits light through the template material. When alcohol is used as the cleaning agent, for example, radicals can be generated using light having a wavelength of 250 nm or less. (Fourth embodiment)
The template cleaning method according to the present embodiment is a cleaning method for effectively removing resist residues generated on the pattern surface of the template. The main difference between the cleaning method according to the present embodiment and the cleaning method according to the first embodiment is the method of supplying the cleaning agent to the template. Therefore, in the following, with reference to FIG. 6, a method for supplying the cleaning agent to the template according to the present embodiment will be mainly described. FIG. 6 is a process cross-sectional view of the cleaning method according to the present embodiment.

First, as shown in the right diagram of FIG. 6A, the template 120 is held in the template cleaning apparatus 500. In the present embodiment, the template 120 is held upward by the template holding mechanism 501. As described above, it is preferable to place the pattern surface of the template 120 upward in order to prevent a gap between the resist residual in the pattern to be cleaned and the supplied cleaning agent 502.

  Unlike the first embodiment, the cleaning apparatus 500 used when performing the cleaning method according to the present embodiment does not use a cleaning tank as the cleaning agent supply mechanism 503 but employs a humidity adjustment mechanism. The humidity adjusting mechanism adjusts the humidity in the apparatus 500 by supplying the vaporized or misted cleaning agent 502 into the apparatus 500 and supplies the cleaning agent 502 to the pattern surface of the template. It is preferable that the humidity adjusting mechanism is configured to be able to independently control the humidity in the vicinity of the pattern surface of the template 120 and in the vicinity of the surface opposite to the pattern surface. The light irradiation mechanism 504 is disposed in the vicinity of the surface opposite to the pattern surface of the template 120 as in the first embodiment. In addition, the humidity-controlled atmosphere is controlled so as not to go around between the template 120 and the light irradiation mechanism 504.

The left figure of Fig.6 (a) is the figure which expanded the dotted-line part of the right figure of Fig.6 (a). Hereinafter, the description using FIG. 6 will be made with reference to only an enlarged view similar to that shown in the left diagram of FIG.

After exposing the template 120 in which the resist residue 124 is generated to an atmosphere of 45% humidity at room temperature using the humidity adjusting mechanism, the template 120 is cooled to form the surface of the template 120 as shown in FIG. Washing water 502 was condensed on the surface of the resist residue 124.

As described above, as a method of supplying the cleaning agent 502 to the pattern surface of the template 120 by condensation, an atmosphere of saturated humidity is formed at the first temperature by the cleaning agent supply mechanism (humidity adjustment mechanism), and the atmosphere is It can be easily carried out by bringing it into contact with the pattern surface (cleaning surface) of the template 120 having a temperature lower than the first temperature.

When functional water is used as cleaning water 502 in this method, oxygen water, ozone water, or hydrogen peroxide water is obtained by bringing oxygen, ozone, hydrogen peroxide into contact with the condensed water and dissolving it in the condensed water. Can do.

As in the above-described embodiments, also in the light irradiation step according to the present embodiment, the light irradiation mechanism is in contact with the surface opposite to the pattern surface of the template 120 and on the side opposite to the pattern surface of the template 120. It is desirable to perform light irradiation from the surface.

When light irradiation is performed without bringing the light irradiation mechanism into contact with the template 120, absorption of irradiation light in the optical path medium from the light irradiation mechanism to the surface opposite to the pattern surface of the template may be suppressed. Specifically, it is desirable to reduce the moisture content of the atmosphere in the vicinity of the surface opposite to the pattern surface of the template by the humidity adjusting mechanism, and prevent condensation on the surface opposite to the pattern surface. For example, dew condensation can be suppressed by heating the vicinity of the surface opposite to the pattern surface of the template or keeping it in a dry state.

Next, as shown in FIG. 6C, the light 105 having a wavelength of 172 nm was irradiated from the surface opposite to the pattern surface of the template 120 using a light irradiation mechanism equipped with a Xe excimer lamp. Although light having a wavelength of 172 nm is slightly absorbed by the template base material quartz, it is applied to the resist residue and the condensed water around it. OH radicals are generated in the dew condensation water 502 excited by light irradiation, and the OH radicals start to react with the resist residue 124.

Since the surface of the resist residue 124 is gradually made hydrophilic by the OH radical reaction, condensation proceeds at the interface between the resist residue 124 and the template 120, and water condensed at the interface is excited by light, and this reaction is repeated. Eventually, the resist residue 124 peels from the template interface. On the other hand, oxygen in the atmosphere is also excited by light having a wavelength of 172 nm to generate oxygen radicals. These oxygen radicals also act on the resist residue and the oxidative decomposition reaction proceeds.

As shown in FIG. 6D, while the resist residue 124 peeled from the template 120 is irradiated with light having a wavelength of 172 nm, oxygen generated from water and oxygen generated from water in the cleaning agent 502 is further added. Under the action of radicals, dissolution and oxidative decomposition progress, and finally complete decomposition into water, carbon dioxide, carbon disulfide and the like.

Finally, as shown in FIG. 6 (e), the temperature of the template 120 was raised and the condensed water 502 was vaporized to complete the cleaning. If the hydrophilicity (OH) and decomposition by the cleaning agent 502 excited in this manner are sufficiently advanced and the vapor pressure of the reaction product between the cleaning agent 502 and the resist residual 124 is high, the temperature of the template 120 is raised. Since the cleaning agent 502 and the reaction product can be easily vaporized only by this, cleaning in a dry state becomes possible.

If a water mark is generated in the process of vaporizing the condensed water due to the temperature rise of the template, a water washing treatment may be added, or the water washing treatment may be performed from a low temperature and dried. Also good. Further, isopropyl alcohol or the like may be used for drying.

When the template condensed with the cleaning agent as in the present embodiment is irradiated with excitation light from the pattern surface after condensation as in the method disclosed in Patent Document 3 or 4, the surface of the resist residue is caused by OH radicals and oxygen radicals. Although the decomposition reaction proceeds, since the decomposition reaction is only in the direction from the resist residual surface, it takes twice or more time as compared with the cleaning method according to the present embodiment.

As a result of analysis, as in the cleaning method according to this embodiment, it is possible to effectively penetrate and decompose water at the interface between the template and the resist residue by irradiating light through the surface opposite to the template pattern. It was also found that the light gained through the residue accelerated the OH radical reaction and oxygen radical reaction on the residue surface, so that a time gain was obtained.

As described above, the cleaning method according to the present embodiment supplies the cleaning agent by dew condensation on the pattern surface of the template to be cleaned, but other cleaning agent supply methods are also conceivable. For example, the cleaning agent is bubbled by the cleaning agent supply mechanism to the template held with the pattern surface facing upward, and the cleaning agent is supplied in the mist state without condensation on the pattern surface (cleaning surface) of the template. Is also possible.

In order to use functional water in this manner, desired oxygen water, ozone water, and hydrogen peroxide water can be supplied to the cleaning surface by appropriately setting the oxygen concentration, ozone concentration, and hydrogen peroxide concentration in the bubbling gas.

When the hydrophilicity (OH) conversion and decomposition by the cleaning agent excited by this method are sufficiently advanced, and a substance having a high vapor pressure is obtained as a reaction product between the cleaning agent and a foreign substance, the template temperature is raised. Since the cleaning agent and the reaction product can be easily vaporized simply, cleaning in a dry state becomes possible.

Even in the light irradiation step in the template cleaning method using this cleaning agent supply method, light irradiation is performed from the surface opposite to the template pattern surface with the light irradiation mechanism in contact with the surface opposite to the template pattern surface. It is desirable to do.

When light irradiation is performed without bringing the light irradiation mechanism into contact with the template, light absorption in the medium from the light irradiation mechanism to the surface opposite to the pattern surface of the template may be suppressed. Specifically, it is desirable to prevent the supply of the cleaning agent to the vicinity of the surface opposite to the pattern surface of the template. For example, a mist-like cleaning agent may be supplied only to the pattern surface (cleaning surface) of the template.

The cleaning method according to each of the above embodiments is not limited to cleaning of a template used in an imprint method in which light exposure is performed, and a template material is synthesized even if it is a template used in imprint using thermosetting without using light. Any member that can transmit light necessary for generating OH radicals, such as quartz and sapphire, can be applied in the same manner.

In each of the above embodiments, the resist residual generated on the pattern surface of the template is a removal target, but the removal target is not limited to the resist residual. By the same method, it is also possible to set the organic matter adhering to the template to be cleaned.

Using the template cleaned by the cleaning method according to each of the above embodiments, a resist pattern is formed on the semiconductor substrate by a method as shown in FIG. It can be manufactured.

1 is a schematic view of a nanoimprint apparatus according to a first embodiment of the present invention. Process sectional drawing which shows the pattern formation method using the nanoimprint method which concerns on 1st embodiment of this invention. Sectional drawing of the template which shows the resist residue produced when the nanoimprint method is used. Schematic which shows the washing | cleaning apparatus of the template which concerns on 1st embodiment of this invention. Process sectional drawing which shows the washing | cleaning method of the template which concerns on 1st embodiment of this invention. Process sectional drawing which shows the washing | cleaning method of the template which concerns on 4th embodiment of this invention.

Explanation of symbols

105 Irradiation light (excitation light)
110 Substrate to be processed 112 Imprint resist 113 Imprint resist pattern 120 Template 124 Resist 402, 502 remaining on template Cleaning agent

Claims (5)

A step of holding a template having a pattern surface having irregularities;
A cleaning agent supplying step of supplying a cleaning agent to a region containing foreign matter attached to the pattern surface of the template;
A cleaning agent excitation step of irradiating radiation from the surface opposite to the pattern surface of the template, and photoexciting the cleaning agent with the emitted light to generate radicals;
A foreign substance hydrophilizing step of making at least a part of the foreign substance hydrophilic by reacting the foreign substance with the radical;
After the hydrophilization step, a foreign matter removal step of removing the foreign matter from the template;
A method for cleaning a template, comprising: The template cleaning method according to claim 1, wherein the cleaning agent that generates radicals is water, an aqueous solution containing water as a solvent, or an aqueous solution containing hydrogen peroxide as a solute . 3. The template cleaning method according to claim 2, wherein the cleaning agent contains oxygen or ozone as a solute. The template cleaning method according to claim 3, further comprising a step of decomposing the hydrophilic substance using the photoexcited oxygen or ozone. Applying an imprint material on the substrate to be processed;
Cleaning the template by the template cleaning method according to any one of claims 1 to 4,
Contacting the imprint material with the cleaned pattern surface of the template ;
Curing the imprint material with the template in contact with the imprint material;
Releasing the template from the imprint material;
A pattern forming method comprising:

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